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I don't think you can just jump to this conclusion, have you done tests in CM to prove it?  Or are you talking about your impression while playing the game?  What were the angles of the opposing tanks?  What were the height differences?  

 

In a real game we are never going to see a range setup with two tanks on level ground at set distances from each other.  

 

In my opinion, there are way too many things going on under hood to make a determination that something is broken.  I don't think this is something to really get all defensive and aggressive about either, I trust that Charles has put the best information he could find in the code and I am comfortable with the simulation of armored combat as it stands. We had a lot of discussion when CMBN was coming out about the armor and AT round modeling, those threads can be found with a search I'm sure... also see my CMBN BETA AAR (first link below) where Charles makes a rare appearance (through a quote in one of my posts) explaining some of this,

 

Read the previous sections of the thread, in which i detail the fact that I have done tests

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Read the previous sections of the thread, in which i detail the fact that I have done tests

 

Really?  Seriously I think it's your attitude that is rubbing me the wrong way rather than the actual subject of your posts which I find interesting.  

 

I did of course read what you wrote:

 

 

 

After considerable testing in CMBN, I have determined (as many here already are aware) that the Tiger deflects almost all 76mm hits from the front at ranges well within the penetration zone for the 76mm gun at low obliquity at ranges of 500 to 1000m. In my estimation, there seems to be no reason what-so-ever that the 76mm gun should not be able to reliably penetrate the Tigers frontal armor at reasonable angles under 1000m.

 

That means nothing to me.. I can't tell if you made a test scenario and ran the tests a hundred times, or if you are talking about your impressions while playing the game over several years?  

 

If the former where are your numbers?  What does your map look like, what distances were tested? How many shots were tested? etc...  Your comments and findings are meaningless without some solid numbers and a test file that can be used to confirm or refute your arguments.  There is no way Battlefront will ever make any changes with the approach you are taking with this thread.

 

 If the second case, then your tests are meaningless.

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Really?  Seriously I think it's your attitude that is rubbing me the wrong way rather than the actual subject of your posts which I find interesting.  

 

I did of course read what you wrote:

 

 

That means nothing to me.. I can't tell if you made a test scenario and ran the tests a hundred times, or if you are talking about your impressions while playing the game over several years?  

 

If the former where are your numbers?  What does your map look like, what distances were tested? How many shots were tested? etc...  Your comments and findings are meaningless without some solid numbers and a test file that can be used to confirm or refute your arguments.  There is no way Battlefront will ever make any changes with the approach you are taking with this thread.

 

 If the second case, then your tests are meaningless.

Im not sure how I could have said that any other way. I just said that you should read the previous sections, since you didnt seem to know that I had mentioned the tests. There isnt any attitude man, just directing you to something it appeared to me you missed. 

 

As you the second quote, I used the word "testing", which to me at least means "testing" as opposed to general play. Sorry for the confustion, but I dont know how else I could have worded that. 

 

As for my numbers: I did 100 test firings on flat terrain for each range (at normal). I tested at 500m, 800m, and 1000m. I recorded PP's and hits as non penetrations, and penetrations as, well...penetrations.

 

At 500m, I got 74 failures and 26 success's. 

 

800m was 79 failures and 21 pens. 

 

1000m was 68 failures and 32 pens. 

 

I dont have any test files, and dont know how I would make one. But there are some other tests on these forums that got very similar numbers. 

 

No I cant prove it, but if you have any doubts do some testing on your own, I guarantee you'll get the same results. As for battlefront, Im presuming that they already know this is the case. I dont need to convince them that their gamer operates in a certain way, since they are well aware that this is the case. The crux of the issue is whether or not it should be that way at all. Rexford has mad several posts on the subject on these very forums, and from other tinkering I have done, it appears that CMx2 follows his book practically to the T. BF has even stated (on these forums no less) that he was a significant contributor to the game. 

 

Anyhow, Im glad you find my post interesting. There isnt any "attitude" here, like I said, from what you posted it seemed to me like you hadnt read my older posts. :)

Edited by shift8

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That's the kind of information that Battlefront likes to see.  Let me ask you this, how many of the PP hits were there at each range listed?  Personally I think those should also be counted as penetrations as they have an effect beyond what a bounced round would have and really they are penetrations even if the round doesn't fully enter the interior of the tank.

 

Thanks for laying out the numbers for me, now I am beginning to understand your concern.. I don't know that I agree yet, but at least we are on the same page and talking the same language.  

 

I think it's interesting that the penetration percentage is higher at 1000m than it is at 500m.. of course 100 hits might not be a large enough sampling to really get accurate numbers.

Edited by Bil Hardenberger

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As for my numbers: I did 100 test firings on flat terrain for each range (at normal). I tested at 500m, 800m, and 1000m. I recorded PP's and hits as non penetrations, and penetrations as, well...penetrations.

 

At 500m, I got 74 failures and 26 success's. 

 

800m was 79 failures and 21 pens. 

 

1000m was 68 failures and 32 pens. 

 

I dont have any test files, and dont know how I would make one. But there are some other tests on these forums that got very similar numbers.

 

The way I read this is you need to clean up your presentation and back it up with test scenarios, saved games, tables from sources and point out where things diverge from your expectations.  After following this thread I cannot get a clear picture in my head of what you are saying the problem is or how you think things should be.

 

Also your data presentation you just gave raises alarm bells for me because you say you counted hits, penetrations and partial penetrations but then you list only penetrations in the "table" and in earlier text you said you don't count partial penetrations - but gave no justifying reason for that.  So, I for one, have no idea what your data is saying and I don't see you clearly articulating what you think should be different.

 

BFC have done a lot of research - it constantly amazes me how much they do - so if you want to see changes in the way the game behaves the bar is set pretty high.  You need to show how the game is behaving currently - and suffer the scrutiny of your test methods.  Then you need to show the real live research that indicates that the game has things wrong - and suffer the debate and scrutiny of your interpretation of that.  So far I'm not seeing anything convincing.  There is to much murkiness in your discussion about test data, test methodology and no clarity in your proposal for what needs to be changed.

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...  

 

I think it's interesting that the penetration percentage is higher at 1000m than it is at 500m.. of course 100 hits might not be a large enough sampling to really get accurate numbers.

 

As I understand it, that could point to the shatter-gap theory - from what limited amount I've read on it, it's supposed to come into effect at closer ranges and then drops off again further out.

 

I'll see if I can find the quotes I looked up - but I can 't promise that they are in any way authoritative ( one, I think, links to some American test firings. )

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As I understand it, that could point to the shatter-gap theory - from what limited amount I've read on it, it's supposed to come into effect at closer ranges and then drops off again further out.

 

I'll see if I can find the quotes I looked up - but I can 't promise that they are in any way authoritative ( one, I think, links to some American test firings. )

 

Thanks for that.. regarding the test firings that have been mentioned throughout this thread and are the basis for the main argument.. do we know how many actual rounds were fired at Tiger tanks?  Were they fired at actual Tiger tanks or at armor mockups?  Were they fired at separate Tiger tanks/armor mockups?  This last point is important because armor will degrade the more it is impacted so those tests could be flawed.

Edited by Bil Hardenberger

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I dont have any test files, and dont know how I would make one. But there are some other tests on these forums that got very similar numbers. 

 

No I cant prove it, but if you have any doubts do some testing on your own, I guarantee you'll get the same results.

A test file would simply be the scenario you set up to get your results before you hit the go button.  You just upload your scenario somewhere so someone else can run your scenario and check your results - or perhaps recommend a better test setup if necessary.  If you want something like this changed it simply isn't going to happen unless you can show that something absolutely definitive is in error and the basis for why you believe that an error is present.  Nobody is trying to give you a hard time.  We just know how difficult it is to get something like this altered. 

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I'll have free time this evening, I could set up a test. It's obvious there's quite a bit of issues with the original methodology.

So, should we brainstorm more effective test conditions? Sample size? I'll obviously count anything that degrades the performance of vehicle and crew as a hit. But how many hits should we record and at what distances?

Edited by Rinaldi

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Thanks for that.. regarding the test firings that have been mentioned throughout this thread and are the basis for the main argument.. do we know how many actual rounds were fired at Tiger tanks?  Were they fired at actual Tiger tanks or at armor mockups?  Were they fired at separate Tiger tanks/armor mockups?  This last point is important because armor will degrade the more it is impacted so those tests could be flawed.

There are no test firing agaisnt Tigers with the 76mm gun that show shatter gap. To my knowledge, there arent any Tiger vs 76mm tests at all, Rexford certainly didnt mention any. The only historical anecdotes I recall him using that specifically mentioned Tigers were from "Faint Praise," which were supposedly from Normandy and therefore impossible. As I mentioned before, there were no Tigers at all on the American front during Normandy, and only 3 confirmed engagements after that.

 

His argument was that supposedly the low nose hardness of USSR and USA ammo caused the armor to displaced too quickly when armor penetration was "too high". About a factor to 1.22. The idea was that at close range you would penetrate because the AP power was so high as to compensate, and then shatter in between, and then penetrate again as velocity decreased. Honestly, that sounds like nonsense to me from the start. He his main data points were some 3 inch gun tests with M-62 and some British 6 pounder tests. I will detail his points and my specific concerns below. 

 

1. Faint praise is the only insinuated actual Tiger v Sherman account, and its demonstrably a case of poor anecdotal evidence. 

 

2. British 6 pounder tests where rounds shattered on a Tigers side armor. Interesting, but not 76mm gun tests, and he makes the assumption that shatter gap is a cause. 

 

3. 3 inch test firing against 3 inch plate at 30 degrees and 40 degrees. He takes these and records the velocity ratios of rounds that failed to penetrate (apparently disregarding all ones that didnt fail) then presumes that the reason certain rounds failed was due to his theory about shatter, and then builds he tables from it. The entire thing is a massive Non-Sequitur comprised of circular logic, as the "gap" is not necessarily the cause. Keep in mind the main issue here is that he is inserting shatter gap as the cause of failures in several non-connected tests, is a potential explanation. 

 

4. He also mentions the Isigny Panther tests where 76mm penetrated the mantle at 200m rather than 500m. Once again, he assumes shatter gap could be the cause, despite the fact that not very many rounds were fired in the first place, and we dont know how they struck the mantlet. 

 

I might be forgetting something, Im sure someone will correct me on it :) 

Edited by shift8

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A test file would simply be the scenario you set up to get your results before you hit the go button.  You just upload your scenario somewhere so someone else can run your scenario and check your results - or perhaps recommend a better test setup if necessary.  If you want something like this changed it simply isn't going to happen unless you can show that something absolutely definitive is in error and the basis for why you believe that an error is present.  Nobody is trying to give you a hard time.  We just know how difficult it is to get something like this altered. 

My test scenario could be duplicated easily. Place two Tigers On one side on flat terrain at specified Range. Then place several shermans shoulder to shoulder opposite them. Make sure Tigers and shermans are immobilized to keep them from changing angle or moving. Make sure angle is as close to normal as feasible. 

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Id like to note one thing while were discussing this. 

 

There might very well be a threshold for rounds with less than 59 rockwell hardness failing at certain velocities, BUT it would HAVE to fall inside the tolerances of the other data. 

 

Specifically, there is the are the American and other nations penetration tables for the 76mm gun, which are more or less in agreement. And there are the shoeburyness  tests where M62 defeats 100mm plate at 30degrees at least twice, which is higher than the average values for 50% success criteria. So the way I see it, some rounds might shatter, but they'd be inside that other 50% of shots, and they would be sharing that space with rounds that penetrated more than the 50% success criteria allows for. 

 

Sidenote: Overall I think BFC and Rexford have their stuff very squared away, this is really the only issue I have found in CMx2. 

Edited by shift8

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1. Faint praise is the only insinuated actual Tiger v Sherman account, and its demonstrably a case of poor anecdotal evidence.

I have not read Faint Praise so I don't know exactly what events Rexford is referring to. However, when mentioning Faint Praise in his book he wrote "Allied" experience in Normandy, not US. I seem to recall that the British had M10 tank destroyers.

 

2. British 6 pounder tests where rounds shattered on a Tigers side armor. Interesting, but not 76mm gun tests, and he makes the assumption that shatter gap is a cause.

Alternative theories are always welcome ;)

 

3. 3 inch test firing against 3 inch plate at 30 degrees and 40 degrees. He takes these and records the velocity ratios of rounds that failed to penetrate (apparently disregarding all ones that didnt fail) then presumes that the reason certain rounds failed was due to his theory about shatter, and then builds he tables from it.

 

I don't see where you are getting this. If you mean the U.S. Navy test on pg 31 there is a penetration at 2065 fps.

 

4. He also mentions the Isigny Panther tests where 76mm penetrated the mantle at 200m rather than 500m. Once again, he assumes shatter gap could be the cause, despite the fact that not very many rounds were fired in the first place, and we dont know how they struck the mantlet.

That is true. There is an assumption that the testers knew what they were doing and would not have made those conclusions without observing fair hits.

Edited by Vanir Ausf B

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Also a quick note on the Shoeburyness test. As I recall, the 100mm test plate was 210-220 BHN compared to 300-340 BHN Tiger RHA. With good quality ammo that would not make much of a difference but if the ammo was low hardness it might. Besides that possible issue is Rexford's note that the low quality ammo was sourced from one of three manufactures, so it's entirely possible the Shoeburyness tests used good ammo but actual rounds in the field were of uneven quality (Combat Mission's ballistic modeling appears to operate under this assumption).

Edited by Vanir Ausf B

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Also a quick note on the Shoeburyness test. As I recall, the 100mm test plate was 210-220 BHN compared to 300-340 BHN Tiger RHA. With good quality ammo that would not make much of a difference but if the ammo was low hardness it might. Besides that possible issue is Rexford's note that the low quality ammo was sourced from one of three manufactures, so it's entirely possible the Shoeburyness tests used good ammo but actual rounds in the field were of uneven quality (Combat Mission's ballistic modeling appears to operate under this assumption).

That is another issue, there were 3 manufacturers, and according to on the threads Rexford was in, only the rounds made by Chevrolet had the issue. So 1 out of 3. 

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I have not read Faint Praise so I don't know exactly what events Rexford is referring to. However, when mentioning Faint Praise in his book he wrote "Allied" experience in Normandy, not US. I seem to recall that the British had M10 tank destroyers.

 

Alternative theories are always welcome ;)

 

 

I don't see where you are getting this. If you mean the U.S. Navy test on pg 31 there is a penetration at 2065 fps.

 

That is true. There is an assumption that the testers knew what they were doing and would not have made those conclusions without observing fair hits.

1. It refers to the American experience. 

 

2. Sure, is it not possible that the rounds used were of a poor batch? As I recall, Rexford only shows 4 hits that shattered in his book. Hardly a statistical cornerstone. 

 

3. In Summary, he inserts shatter gap into those 3 inch tests as the cause. Perhaps in some cases there was a shatter issue. But hardly grounds for the conclusions he comes to later with his rather precise charts. 

 

4. That is a unreasonable assumptions IMO. The Isigny tests were hardly scientific in nature, and essentially amounted to "hey lets get some panthers and lob some stuff at them." Heck, the Panther wasn't even on level ground. Do we even know the hits were at normal? As I recall those tests make no mention of that. And I think its a dangerous precedent to simply assume unknown factors, especially when trying to prove something that doesnt have any actual data specially meant for the purpose. Even if we consider the testers as competent as you mention, they might have considered any hit on the mantle a fair hit when you consider that in they eyes of the tester, it might not have been considered practical to single out the center mantle since its very possible that round would not strike that area in battle. 

 

And I'd like to point out again that the American penetration tables, and penetration tables for the same gun from other nations verify the 76mm guns performance with 50% success criteria. IF shatter gap was a thing, it only exists on the other sides of that. Besides this, Ill say again that the section on this is Rexfords book is totally guess work. Maybe there was a shatter potential for the M62 (as if any round isnt susceptible to this under the right conditions) but the extreme stance of Rexford and the game is not justified without better proof IMO.

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It is my understanding that Charles does not exclusively use Rexford's book for the penetration data so I'm not sure focusing solely on Rexford's work is necessarily going to move the ball forward.  Is 'shatter gap' something exclusive to Rexford or are there other researchers and sources of information that discuss this topic?

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It is my understanding that Charles does not exclusively use Rexford's book for the penetration data so I'm not sure focusing solely on Rexford's work is necessarily going to move the ball forward.  Is 'shatter gap' something exclusive to Rexford or are there other researchers and sources of information that discuss this topic?

Maybe, but If there are I havent seen them. I havent seen any offical sources discuss it, and anyone a forum talking about brings up Rexford. But there could be. If someone has it, bring it forward :)

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Which version of the 76mm gun? There was a 76/L52 and 76/L55

 

The 76/L55 APCR has a penetration rating of 160 mm of armor at 500 meters and 181mm at 100 meters.

 

post-73942-0-46594800-1437623396_thumb.p

Edited by user1000

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Shatter gap is a thing. Rexford did not invent it out of thin air on a sleepless night.
 
I don't have this book (it costs over 100 dollars) but the guy who wrote it is a bonafide expert in the field.
 

...it is possible to perforate the target at relatively low velocities followed by partial penetration at higher velocities. Perforation of the target again occurs when the velocity of the projectile is increased further. This occurs because the penetration mechanism of the projectile changes as the velocity is increased.


Armour: Materials, Theory, and Design
 
Rexford also references an article in the Journal of Impact Engineering, although the photocopy of the table from it in his book is poor quality and only partially legible.
 
How this applies to US 76mm does involve some extrapolation and educated guesswork, but I have read comments regarding Rexford's shatter gap work by people who know their stuff (Paul Lakowski, John D. Salt, "Mobius") and none of them have raised objection to his methodology or conclusions that I am aware of.

Edited by Vanir Ausf B

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Shatter gap is a thing. Rexford did not invent it out of thin air on a sleepless night.

 

I don't have this book (it costs over 100 dollars) but the guy who wrote it is a bonafide expert in the field.

 

Armour: Materials, Theory, and Design

 

Rexford also references an article in the Journal of Impact Engineering, although the photocopy of the table from it in his book is poor quality and only partially legible.

 

How this applies to US 76mm does involve some extrapolation and educated guesswork, but I have read comments regarding Rexford's shatter gap work by people who know their stuff (Paul Lakowski, John D. Salt, "Mobius") and none of them have raised objection to it that I know of.

Sure, projectiles can shatter. The dispute is whether or not it affects 76mm M62 so greatly that it happens almost every time. When I say shatter gap isnt a thing, I am referring to its relationship with M62 APC, specifically the severity of it. The fact that rounds can shatter is beyond doubt. I've even said that or implied that several times already. If my posting made this unclear, then my bad. 

 

As for the Tank.net people you mentioned, respectfully, I dont take anyone on a forum seriously---at least not like that. It means absolutely nothing to me with regards to who are the "big shots" of the forum space. They are probabaly good people and smart/ knowledgeable etc, but their lack of objection doesnt mean a thing to me. Rexford is a Published author, one I that I agree with totally except on this issue, and I'm not changing my mind just because of that. I'd imagine that I have read the same threads you have, especially since I have seen both of those names in Rexfords Tank net threads on the subject. 

 

What I do not buy at all, is the modeling in game, where the great majority of M62 APCBC fails. As I pointed out eariler, several nations M-62 AP values prove beyond doubt that the M-62 does not shatter agaisnt the specified armor thickness's, at least within a 50% success margin. IMHO, I dont see how that can be reasonable disputed. If the Shattering problem, which arose from one manufactures rounds as stated previously, was so severe as it is in game-----Then it would be evident in those nations tests, as it would have reduced the 50%  penetration values. 

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The dispute is whether or not it affects 76mm M62 so greatly that it happens almost every time.

 

What I do not buy at all, is the modeling in game, where the great majority of M62 APCBC fails.

 

If this is your primary concern then I have some good news: You're wrong! :lol: Shatter gap is barely even in the game from what I can tell.

 

M4A3 Sherman 76 vs Tiger I late @ 500m (sample size 325)

Full penetration: 11%

Partial Penetrations: 63%

Spalling: 22%

No Effect: 4%

 

Pz IV ausf H vs Tiger I late @ 750m (sample size 328)

Full penetration: 16%

Partial penetration: 57%

Spalling: 23%

No effect: 3%

 

Only hits on the driver plate were counted (the "Superstructure Front Hull" in-game). The Tigers were angled about 10° away from the shooters in order to match Rexfords shatter gap criteria.

 

This is a very good apples to apples comparison. The Sherman's penetration at 500 meters is identical to the Pz IV's penetration at 750 meters (116mm). They also use the same shell type (APCBC with HE burster) and have virtually the same diameter.

 

If you look at the percentage of hits that were penetrations of some type between the two guns they are identical (73.5% and 73.8%). Spalling and no effect ratios are also identical. The only significant difference is that a larger percentage of Pz IV penetrations are full rather than partial, but the difference is small, 5% of total hits.

 

So contrary to claims that shatter gap modeling in the game is "severe" or "extreme" it appears to be very subdued, to the point of near-irrelevance unless there are other conditions under which it is more pronounced.

 

https://www.dropbox.com/s/0k16bdi28leb03k/Pz%20IV%20750m%20shatter%20001.bts?dl=0

 

https://www.dropbox.com/s/wjndw7soxkdzd6f/Sherman76%20500m%20shatter.bts?dl=0

Edited by Vanir Ausf B

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